1. The Field of the Invention
The present invention relates to centrifuges and, more specifically, small table top centrifuges having minimal components and reduced noise generation.
2. Present State of the Art
Centrifuges, and particularly small table top centrifuges, are used in a variety of different environments for facilitating such services as separating substances of different densities, removing moisture from materials, and for simulating gravitational effects. A conventional table top centrifuge includes a housing enclosing a chamber. Disposed within the chamber is a motor which rotates a shaft. During operation, a substance, typically a solution, is secured by a rotor to the shaft. The shaft and rotor then spin rapidly which produces an increased gravitational force on the substance. Where the substance is a solution, the elements of the solution are separated by density.
Since centrifuges operate at high speeds which produce tremendous forces, the housing of conventional centrifuges is made of plates of high strength steel or other metal. From a manufacturing perspective, such centrifuges are time consuming to assemble and expensive in terms of material costs and labor costs. The resulting product is also relatively heavy, making it difficult to handle and expensive to transport. The high weight and cost are also a burden on the consumer. Furthermore, most conventional table top centrifuges are noisy during operation and thus uncomfortable to work around. Much of the noise is generated as a result of the centrifuge being unbalanced and thus vibrating during operation.
One attempt to solve some of the above problems is disclosed in German utility patent 72 24 033 and corresponding U.S. Pat. No. 3,804,324. The '324 patent discloses a table top centrifuge having a housing in which a motor and central rotor is positioned. The housing includes an encircling side wall having a base and a cover attached thereto. The housing is manufactured from structural high-strength foam, preferably polyurethane high-strength foam. To improve the stability of the centrifuge housing, a metal jacket is embedded within the walls of the housing. Although the metal jacket is perforated to reduce noise generation, the process of embedding the metal jacket during formation of the foamed walls is technically expensive.
A centrifuge is also disclosed in German Patent No. 1,961,734. The centrifuge of the '734 patent has a housing divided into a stationary lower part and an elastically suspended upper part. A centrifugal basket is seated within the upper part of the housing. In this configuration, vibrations of the rotor caused by imbalance are damped. This device, however, does not provide an axial connection of the drive motor and rotor. As a result, a relatively large amount of space is required to mount a separate drive motor as well as the accompanying drive connection. This required increased size makes the centrifuge less appealing to those seeking small table top centrifuges.